Yat (yāt) interj. : A combination of the words "Yay!" used for expressing elation, and "What?," resulting in a word one uses when responding to a statement that may demand an excited response, but the responder is unsure as to whether or not they should be thrilled about said statement.

Person #1: "Hey - ! Would you like to go see the new exhibit at the Museum on the Dromaeosauride families - ?!"